OT: Driving electric cars in winter

[John Rumm]

You sure you don't mean depreciation rather than acceleration?

At 62 bhp/tonne it does not sound like much of a speed demon!

[Chris Hogg]

So who pays? Presumably we do, either in higher electricity charges or through taxation. More subsidies for the green brigade!

[NY]

But it will be constant acceleration without pauses for gear-changes and without reductions where a petrol or diesel engine would develop less power (away from the peak power/torque revs).

I presume electric cars have one fixed gear ratio (maybe even direct drive from motor to axle) without needing a multi-ratio gearbox.

[harry]

I bought it S/hand, 300 miles, ex demo & £7000 off new price. But the taxpayer paid someone £5000.

No, it comes with a 2.2Kw charging lead with 13a plug. It can be fast/rapid charged but I never have.

There is a big "centre-zero" ammeter you can watch to pass time. It looks l ike one but isn't. Dunno whether it's linear or not.

he brakes except for completely stopping.

Yes there's a "dead zone". it's position varies depending on speed and (sli ghtly) battery charge.

The lever changes position and amount of regenerative braking and also tota l power available and power distribution curve.

bedded in after 10.000 miles

This is not a series DC motor. It's a three phase (up to)500Volt permanent magnet motor. However, it behaves like a DC series motor.

It is water cooled & there is a radiator. The water gets maybe tepid.

How they are able to control it is pretty amazing. There are virtually no losses in either the 3 phase inverter or the rectifi er.

It was a petrol engined car. Suspension is a bit primitive, noisy & choppy.

Why such a small car should have power steering I dunno.

Good for 80mph. Don't think you'd get far at that speed.

The traction control/motor is perfect, that aspect is a pleasure to drive, just the general handling is poor-shit. External finish is excellent. Well put together.

[harry]

You presume correctly. Mine has a 60:1 fixed ration gearbox

[harry]

Electric motors can be made with a perfect speed/torque characteristics for traction. ICE are just about s bad as it's possible to be.

So bhp/ton for ICE engines is neither here not there.

[T i m]

My Moke is probably whatever ratio a Reliant Regal / Robin diff was (so much lower than 60:1) and driving Austin Mini 12" wheels.

I just found this:

And if you note around -1.50 it shows the Queen mother on an Enfield

8000 Moke. The previous owner of mine believed it was his and wrote to Buck House for confirmation but whilst he got a reply, they could neither confirm nor deny it was that actual one used.

And apparently it was used (on a run down one of the piers) because it was open top, would fit between the bollards and was quiet. ;-)

You can also see in that clip prototype / hints towards the Moke variant.

Bit of a jump, designing the Enfield electric cars and then Thrust 2! ;-)

Cheers, T i m

[The Natural Philosopher]

generally at least two gears.

[bert]

Dint they try those on the Dreamliner?

[tony sayer]

So a gearbox then?.

Just wondering do motor drives on railway loco's have them ?.

Got a feeling they don't...

[tony sayer]

In article , Chris Hogg scribeth thus

Yes the leccy car brigade don't see that as a problem!...

>

[John Rumm]

Indeed...

although even with all that its 0-60 is 13 seconds, which seems to suggest harry's claim that "few car can keep up with it" was perhaps omitting some salient detail? (like few cars can keep up with it unless you start their engines).

Often yes... some even have motors in the wheel hubs.

[John Rumm]

You do talk daft...

[Tim+]

I think that's the exception rather than the rule. I believe some models of the Tesla had a two speed box but in general they're unnecessary for most electric cars.

Tim

[Dave Plowman (News)]

Most car diffs fall into the range of 2-6:1

The original Mini had one between roughly 2.7:1 and 4.3:1 depending on model.

The Reliant Robin, 3.23:1

[harry]

The max torque is at zero revs. So it sets off pretty damn quick.

Wheel hub motors are pretty useless. To much unsprung weight.

[harry]

You're the one talking daft. The ICE is totally unsuited to traction. Only used because it has a portable fuel supply.

[harry]

Drivel.

[T i m]

Ok thanks.

Ok. Our 1300 Mk2 (doner car) came with 3.89(?):1 and is now running

4.44:1 because of the massive wheel circumference increase in the kitcar.

Quite low then. I wonder who made that axle and if a higher ratio diff was available for it?

Cheers, T i m

[T i m]

+1

Being in the Battery Vehicle Society I have seen loads of home brew EV projects and I would say most of those also have, or end up with direct drive. Some retain the gearbox but often only because 1) it's easier for them or 2) the vehicle is a test bed and they can then easier play with things like battery voltages (and hence motor rpm's) without having to change the diff every time.

Cheers, T i m